Orange County now ranks as the third-largest Asian American population nationwide, with nearly 600,000 Asian Americans living in a county once defined by its dominantly white communities, a study to be released Tuesday shows.

In a boom decade running through 2010, the number of Asian Americans living in the county increased 41%, changing the face of cities from Anaheim to Irvine.

Across the United States, Orange County now boasts the third-highest count of Asian American-owned businesses, employing more than 96,000 workers. Those businesses generated more than $20 billion in revenue in 2007 alone, the study found.

"There are a lot of surprises in this study," said Mary Anne Foo, who heads the Orange County Asian Pacific Islander Community Alliance. "This is a place known for more than just the Vietnamese American community. There are Korean, Chinese and Filipino groups, some who are usually ignored. Our hope is that people can start seeing the larger picture."

The alliance worked with Asian Americans Advancing Justice, both in Los Angeles and in Orange County, to compile the data. Though the report relies mainly on U.S. Census Bureau numbers, it also infuses material from the California Department of Education, USC's Center for the Study of Immigration Integration, UCLA's California Health Interview Survey and the U.S. Department of Homeland Security.

Until the new millennium, Orange County's most distinguishing Asian American community was in the central county cities of Garden Grove and Westminster, where Vietnamese immigrants settled, forming the now-sprawling Little Saigon district. Since then, the Asian American growth has moved both north and south.

Irvine is now home to the county's largest Asian American population, and tiny La Palma is the county's first majority Asian American city, with 51% of the population. Asian Americans make up roughly 43% of Irvine's population

The study also found that the number of Pacific Islanders or native Hawaiians increased 17% during the same 10-year period, with much of that growth clustered in Anaheim, Garden Grove, Huntington Beach, Santa Ana and Irvine.

Asian Americans, the study found, have more immigrants than any other racial group in the county, with almost 62% of Asian Americans and 16% of native Hawaiian and Pacific Islanders born outside the United States.

"One of the things that strikes us the most is that these diverse populations experience real needs," said Dan Ichinose, director of the Demographic Research Project for Asian Americans Advancing Justice-Los Angeles. "They've been impacted by the economic crisis. There's a growing homeless crisis. Overall, the groups need to engage more politically."

Between 2007 and 2012, for instance, the number of unemployed Asian Americans in the county jumped 123%. Today, more than 57,000 Asian Americans and 1,700 native Hawaiians and Pacific Islanders are living at the poverty level, according to the report.

"We want policy makers not to look at Asian Americans as a homogeneous group," says Kristin Sakaguchi, research analyst with Asian Americans Advancing Justice-Los Angeles. "Each ethnic group has different needs, and we urge them to understand them to create policies that are more effective."

Anh Do writes for the Los Angeles Times.

anh.do@latimes.com

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